The present invention relates to a process for the extraction of an active principle from at least one yeast for treatment against aging of the skin and particularly to guard against the appearance of wrinkles.
The invention also covers the active principle obtained, the cosmetic compositions which include it as well as the treatment envisaged with this active principle.
There exists a so-called dermo-epidermal junction which constitutes an interface between the derma and the epidermis.
This region is very complicated and performs several particular functions which are involved in the various biological processes such as tissue repair, attachment or differentiation of the epidermal cells.
Thus, the dermo-epidermal junction promotes exchanges between the derma and the epidermis, and takes part actively in epidermal communication.
This dermo-epidermal junction also plays a very important role in the xe2x80x9cmechanicalxe2x80x9d, cohesion between the derma and the epidermis, thanks to specific anchoring molecules, namely:
IV and VII collagens
integrines,
fibernectine.
Thus, the dermo-epidermal junction comprises essentially the basal epidermal membrane, the anchoring febriles and the hemidesmosomes. However, this basal membrane has a high mechanical resistance, due particularly to the pulmerization of this fibrous protein which is collagen IV, present in the form of dimers and tetramers.
Collagen VII itself is the major component of the anchoring febriles. Collagen VII can connect to the end-terminal ends of collagen IV and of fibronectin to form a network.
The integrines are glycoproteins whose surface is constituted of two sub-units xcex1 and xcex2. These integrines are specific as to function of the cellular type which express them. The culture cells express particularly the integrines xcex12xcex21, xcex13xcex21 and xcex15xcex21.
The integrines xcex12xcex21, expressed by keratinocytes and fibroblasts, represent cellular receptors for the type IV collagens as well as fibronectine. These integrines play an important role in maintaining a spatial organization of the dermo-epidermal junction and in the repair/scabbing phenomena.
It is on the quality of the anchorages and hence the connections at the dermo-epidermal junction that the surface condition of the skin depends.
Thus, if the dermo-epidermal junction is strong, with folds ensuring an excellent cohesion between the derma and the epidermis, the skin is slightly wrinkled, whilst any relaxation due to a synthesis of a smaller quantity of anchoring molecules gives rise to a flattening of the interface with a loss of firmness and regularity of the surface of the skin.
The present invention also has for its object to provide an active principle which permits guarding against the effects of cutaneous aging with a deep action, by stimulating the synthesis of the anchoring molecules such as the integrines, the fibronectine and the collagens IV and VII, which promotes maintaining the dermo-epidermal cohesion and tissue repair. Because of this, the depth of the wrinkles decreases and the microcontour of the skin is smooth.
The invention also has for its object the extraction process as well as the cosmetic treatments which consist in using this active principle in a cosmetic composition.